This invention relates to dental prophylaxis (prophy) cups, and in particular to a prophy cup which will more effectively control the pumping or movement of paste from the cavity of the cup.
Rotating prophy cups are generally used both to apply prophy paste to the teeth and to clean and polish the teeth. A prophy cup serves three different functions. It operates as a reservoir which holds prophy paste to be applied to the tooth; it distributes the paste to a working surface of the cup to clean and polish teeth; and it cleans and polishes all surfaces of the teeth, including subgingival and interproximal surfaces of the teeth. Prophy cups typically form a well or cavity into which the paste is inserted, as by dipping the cup in a reservoir of paste. As the cup is rotated by a drive (a prophy angle), the paste exits the cavity and is applied to the tooth. The paste acts as both a lubricant and as an abrasive which removes stains, plaque, and calculus as it is rubbed across the tooth by a working surface of the cup. Presently available prophy cups generally serve well as reservoirs. However, they do not distribute the prophy paste well, nor do they provide large effective working surfaces.
Presently available cups are provided with generally vertical or spiral ribs which are designed to facilitate the cleaning properties of the cups. However, these ribs also facilitate the flow of paste from the cup's cavity. Under the centrifugal forces generated by the cup as it rotates, the paste in the cup cavity quickly exits the cup and splatters on the tooth surface and within the patient's mouth. The cups do not control the flow or exiting of the paste from the cup. The cup, therefore, must frequently be reloaded with paste to perform a single prophy procedure. Further, the quickly diminishing amount of paste present at the interface between the cup and the tooth reduces the amount of abrasion and the cleaning performance of the cup.
When the paste reaches the top surface of the cup, the paste is located primarily in a narrow annular ring, essentially at the edge of the cup. That is, the entire working surface of the cup is not covered with paste. The effective working surface of the cup thus is small.
Cups presently have side walls which are generally straight. Proper cleaning of a patient's teeth requires that the teeth be cleaned subgingivally and interproximally. To clean subgingivally and interproximally with currently available cups, the hygienist must press down on the cup to create a flare which allows the working edge of the cup to penetrate beneath the patient's gum or between the patient's teeth. This requires a fair amount of pressure. Some cups are provided webs which extend inwardly from the inner wall of the cavity. The webs function, in part, to control the amount to which the cup can flare.
Rosenberg, U.S. Pat. No. 5,360,339, attempted to solve some of the problems with distribution of the paste and the working surface of the cup. The Rosenberg cup includes spaced apart ridges or rings on the inner surface of the cup's cavity. The rings are not continuous. Rather, they have aligned gaps formed in them. The rings thus define axial and circumferential channels or grooves. The rings or ridges form the actual working surface of the cup. Thus, the working surface is formed in two discrete annular rings, rather than one large ring. Because the working surface is relatively thick, it may not be able to clean subgingivally or interproximally. Further, it continuously supplies paste to the working surface, rather than supplying the paste only when needed. Rosenberg also provides a flare at the top edge of his cup. However, the flare appears to be too thick to be used either subgingivally or interproximally.